Table top, or toaster ovens have become popular home appliances in many households. One reason is because using a toaster oven saves energy since it takes less energy to heat a smaller oven cavity than a standard wall oven, and the toaster oven can heat up more rapidly, thus decreasing cooking time. One limitation of a tabletop oven in relation to a full size wall oven is the fixed distance between the baking rack or tray and the heating element; in a wall oven, the baking rack is adjustable, so the food can be placed as close to the heating element as desired. If the toaster oven were engineered such that the position of the heating element relative to the baking tray could be adjusted so that the food is closer to the element, the baking time could be decreased and less power could be used, particularly when thinner food such as bread is cooked. The present invention may also preferably include a heat directing plate, which reflects heat from the heating elements back toward the food item, thus maximizing energy efficiency by minimizing heat dissipation.
Another advantage of a moveable heating element is that the user does not have to open the oven to get the food closer to the heat, as when a baking rack is moved. Further, a moveable heating element provides a measure of safety in that the user can move the heating element close to the food for cooking, then move the heating element away from the food when the food is removed from the electronic oven, thereby reducing the possibility of being burned by the heating element.
Attempts have been made to design more efficient tabletop and toaster ovens. Art in this area is described below.
U.S. Pat. No. 6,250,214 discloses an enclosed rotisserie with added convenience, including a countertop resting box-like enclosure housing a safety rear mounted heating element and a power rotated dual rod spit assembly. The gear driven spit assembly may be easily inserted and removed straight into and out of the enclosure without need for angling or coupling the assembly to a power drive socket. The spit assembly may also be mounted at various distances from the heating element to decrease cooking times. The open front of the enclosure is from time to time covered by an inclined glass panel door which may be opened in various ways to facilitate food insertion into and removal from the enclosure, and which may be easily removed for cleaning or other purposes. The embodiment's design makes efficient use of valuable counter space by recessing back and raising off the countertop its controls. Two countertop supported sizes for the embodiment are suggested, one for larger families and entertaining, and the other for small families and singles. Maintenance is minimized by various embodiment parts being removable for cleaning including a cleaning shield located behind the heating element, the glass door, and a drip pan with slotted cover. A variety of foods may be cooked using the spit and accessories that attach to the spit. Such accessories include wire baskets and a rotating stir fryer. Self-rotating kabob rods cook kabobs on all sides evenly and allow for increasing rotisserie capacity by increasing the length of rotating rods available for rotisserie food mounting.
U.S. Pat. No. 7,105,778 describes A combination toaster oven and toaster appliance for cooking and heating foodstuff including a housing defining a food cavity therein and a heating element mounted in the housing for heating the food cavity. The housing includes a top wall and a front wall. A slot is located in the top wall and a door is movably mounted to the front wall. A toaster oven opening is located in the front wall and provides access to the food cavity. The door is movable between a closed position wherein the door covers the toaster oven opening and an open position wherein the door exposes the toaster oven opening and food cavity. A slot cover is movable between an extended position covering the slot and a retracted position exposing the slot.
U.S. Pat. No. 7,317,174 describes a food heating or cooking appliance that has at least one electrical heating element within its interior that is adjustable in position so as to be able to be moved close to thin or small food items under the control of a manually actuated control. A separator plate that extends across the interior chamber of the appliance from side to side and from front to back is movable with the heating element to enable adjustment of the volumetric size of the cooking chamber containing the heating element and the food to be heated or cooked. A manual actuator, a knob or lever, for example, moves the heating element and the separator plate through a motion transfer bar that extends across the width of the appliance and is attached to a linkage on each side of the appliance to communicate movement to a pair of movable supports supporting the rod-like heating element at each of its ends and the separator plate at opposite edges.
The present invention has advantages the prior art lacks. It can cook a greater variety of foods than inventions detailed in some of the examples of the prior art above. The mechanism for moving the heating element in the present invention is elegant in its simplicity, making the present invention easier to maintain, less expensive to manufacture, and easier to use than examples in the prior art.
In the closest prior art, U.S. Pat. No. 7,317,174, the mechanism contains a number of moving parts including a slide bar that can easily jam or bend. In one embodiment of the present invention, the scissoring mechanism yields a fluid, smooth movement that can be stopped with the heating element at any position in the electronic oven body.
In both embodiments of the present invention, the interactive connecting rods are larger and sturdier than the mechanism of the prior art. This allows more force to be applied to the mechanism in a more symmetrical manner, which allows for smoother movement of the mechanism and the heating element than do the smaller slide bars of the prior art. Additionally, the present invention contains stabilizing rods to keep the support and mechanism stable as the heating element moves up and down.
In a preferred embodiment of the present invention, an ingenious interlocking vertical track and interlocking mechanism add great stability to the invention. None of the prior art discloses this interlocking mechanism, and it is believed that this is a novel mechanism.
Another feature of the present invention is that the control knob is connected to a cam mechanism that has multiple preset positions in a preferred embodiment. This increases safety as it also helps keep the heating element in place.
The present invention is an electric oven that has a moveable heating element and a top reflector plate such that the volume of heated space inside the oven is minimized yet is sufficient to cook the desired food.
The invention is an article of manufacture, an electric oven having a body for holding food, with at least one heating element within the body; vertical side slots installed symmetrically on a right side wall and a left side wall of the body with a terminal to connect the heating element to a mechanism art the vertical side slots; and a mechanism that drives movement of the heating element in the vertical direction along the vertical side slots.
The mechanism includes a lifting unit, which in one embodiment is a diamond shaped frame formed by four interactive connecting rods. Two upper interactive connecting rods form the top section of the diamond and are connected with the support, which may be a horizontal bar, and two lower inactive connecting rods form the bottom section of the diamond, and are connected to the revolving shaft that passes horizontally through the oven wall at the bottom of the left and right side walls of the body. The diamond shaped frame uses components, including but not limited to, pins, hinges, or joints at the intersection of the interactive connecting rods to connect them and also allow them to move in a pivoting action when an adjustable knob is turned and the revolving shaft is activated.
The connecting section of the revolving shaft is square and the corresponding hole of one of the lower interactive connecting rods is square to avoid slip, while the corresponding hole of the other lower interactive connecting rod is round. When the revolving shaft is rotating, the interactive connection rod with the corresponding square hole will be driven so that the interactive connection rod linked to it will be driven upward or downward, and, as a result, upward or downward movement of the heating element will be achieved. An adjustable knob is installed at the outer side wall of the electric oven, with the revolving shaft connected to it so that the motion of the shaft, and therefore the position of the heating element, can be controlled by a user.
When the knob is turned to the ‘low’ position, the four rods are in the collapsed position; when the knob is turned to the ‘high’ position, the four rods are in the extended position. The knob can be set so that the heating element stops at any of four points; in an alternate embodiment the heating element can be set at any interval between the high and low positions.
The mechanism is disposed on both the left side and the right sides of the electric oven, with identical elements of the mechanism on both sides except for the adjustable knob, which is disposed on only one side of the electric oven. In a preferred embodiment, the mechanism is concealed by an outer wall, so that is disposed between an inner and outer oven wall, and is not visible unless the oven is disassembled. Disposing the mechanism on both the right and left sides of the electric oven adds to the stability of the heating element in any vertical position. A spring may also be disposed on the mechanism to add stability and safety. In addition, there are stabilizing rods located on each side of the electric oven that stabilize and smooth the movement of the heating element.
In order to heat food more quickly, a heat reflecting plate may be disposed above the heating element to reflect heat down onto the food. The heat reflecting plate is disposed such that it moves with the heating element, by affixing it to one or more sides of the heating element. Alternately, the heat reflecting plate may move independently of the heating element.
A second embodiment of the invention is an article of manufacture that is an electric oven having a body for holding food with a vertically moveable heating element; an L-shaped lifing unit with a lower interactive connecting rod and an upper interactive connecting rod; an attached spring connected to a support bar that traverses vertical tracks; and a terminal to connect a heating element to the lifting unit.
The present invention is an improvement over the prior art because it has a design that is versatile, yet less complicated and therefore easier and less expensive to manufacture.
It is an object of the invention to provide a faster cooking method for small volumes of food.
It is an object of the invention to use less energy for cooking food.
It is an object of the invention to provide a means to adjust the volume of space that must be heated to cook food.
It is an object of the invention to provide a tabletop electric oven with an adjustable heating element.
It is an object of the invention to provide a tabletop electric oven with a heat reflecting plate above the upper heating element.
It is an object of the invention to provide a tabletop electric oven with an adjustable heating element that is easy to use.
It is an object of the invention to provide an improved mechanism for adjusting the height of the heating element in a tabletop electric oven.